If you don’t have any soldering experience, I would say it’s best to just buy another board that already has ISA slots. Soldering an ISA slot is not an easy task, unless you’ve been doing this type of work for a longer period of time (which, obviously, is not the case… since you’re asking this question).

Depending on your location, you could still find 440BX motherboards for as little as $20. Try to avoid eBay, because prices there are usually crazy high. Your best chance of finding good deals is on local classifieds.

You're right, I don't have any experience. Thanks for the advice. Thinking about it now, it would be a shame to mess up an old motherboard like that.
I have my doubts that anyone will be selling motherboards in my area, but when I have some fun money I'll see if I can get a better deal, or maybe look for old computers at the flea market or something like that.

What sort of motherboard are we talking about here?

If it's a unicorn and you're inexperienced in soldering I fully agree: don't run the risk.

But if it's an otherwise unremarkable board (this sounds like a pretty generic Via 693A / 694X thing), and you can afford to lose it if you mess up, it might well be a good learning project. ISA slots aren't that hard - they're just basic through-hole objects with decent pitch between the pins. It would only get challenging if you need to add additional SMD components. That requires more skill & equipment - and is another reason to tell us exactly which board it is and take a good photograph of the area around the slot.

Best-case you would only need to do the slot. Worst-case it would be a board with a chipset without native ISA support that would require soldering a PCI-ISA bridge chip as well as support logic and buffers...

One thing you can do in any case is order a dirt-cheap soldering kit from AliExpress just to get the feel. Anything will do, a simple digital clock kit has soldering of similar level of difficulty.

Is it the only ISA slot on the board? If so it's likely there are other (smaller) missing components as well that are required for the slot to work.

The biggest challenge with adding an ISA slot isn't the soldering. It's going to be removing the existing solder used to fill the holes. Since that solder is likely to be lead-free, it requires more heat to melt. That coupled with any solder connected to a ground plane (which absorbs a lot of heat) makes solder removal a challenge.

This is where the real risk of damage is, because using too much heat or for too long with an iron can potentially damage solder pads.

If you're not experienced with desoldering, I wouldn't attempt this on this board because the risk of causing damage is high.

I do know how to solder, and trying to mount a PCIE x1 on a board the has it in some versions, clearing the holes is an absolute pain, would not recommend.
Ideal solution, find a friend with a desolder station, like a haku (I call it a moo moo, for the noise when it's pumped).
half assed solution, a decently powerful temperature-controlled iron as the ground plane really sucks heat away, and alternate braid or plunger solder sucker, also apply leaded solder (or better, low melt) to help the original melt.
Practice on a dead board first!

super_teatime wrote on 2026-05-28, 05:07:

Hi there. This is my first post here. I have an old Pentium 3 motherboard laying around with an empty space for an ISA slot to b […]
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Hi there. This is my first post here.
I have an old Pentium 3 motherboard laying around with an empty space for an ISA slot to be soldered on.
Being a fan of the OPL chips, I bought an ESS AudioDrive a while ago and I've been itching to use it.
Is there anything I should know before I go into this project? Any reccomended places to buy an ISA slot adapter?

I added an ISA slot to an MSI MS-6309 that didn't have one (I desoldered the slot from a non-functional, damaged motherboard); the thread is here: Re: Need help with MSI MS-6309
If you don't insist on using AudioDrive and don't want to solder, you can also use one of the PCI cards with a hardware OPL chip (ESS Solo, Yamaha, ALS, etc.).

Shponglefan wrote on 2026-05-28, 10:50:

The biggest challenge with adding an ISA slot isn't the soldering. It's going to be removing the existing solder used to fill the holes. Since that solder is likely to be lead-free, it requires more heat to melt. That coupled with any solder connected to a ground plane (which absorbs a lot of heat) makes solder removal a challenge.

This is where the real risk of damage is, because using too much heat or for too long with an iron can potentially damage solder pads.

If you're not experienced with desoldering, I wouldn't attempt this on this board because the risk of causing damage is high.

100% this